Green Building and ADUs

How do CalGreen Building Code requirements relate to ADUs? CalGreen Mandatory Measures are a requirement of the California Green Building Standards Code. These mandatory measures are required on all new homes and residences. Furthermore, they also apply to additions and alterations which increase the building’s conditioned area, interior volume, or size. 

But be careful, not all measures are necessary for your ADU. Make sure your designer or architect knows this tiny distinction.

When submitting a CalGreen Checklist for an ADU, any items that are not specifically required should be marked as “Not Applicable”.

Gary Welch is the founder of CalGreen Energy Services.

He has spent over 35 years engineering sustainable buildings in California and throughout the world.

Later in my career he moved to Sonoma County and became a principal for a consulting engineering firm. When the CalGreen Code first took effect in 2009 it was the first state building code to mandate sustainable design.

He has now designed more than three hundred CalGreen projects.  Almost every one involved some level of confusion over the application of the CalGreen Code!

Read in detail here.

Photo by Christian Heitz on

One thought on “Green Building and ADUs

  1. […] Make sure the architect includes a CalGreen checklist, a requirement for all newly constructed buildings. And do not let your architect make rookie mistakes. […]

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